Choose Home tab→Modify group→Move Faces list→ Match Flange Face.
Select the flange face you want to match.
Select a target face and enter an offset value if you want to offset the faces.
If you did not enter an offset value, skip to step 5. If you entered an offset value, click to indicate the offset direction.
Click Finish to match the faces.
Tip:
You can also use the Offset step of the Flange command to create a flange offset from a selected edge, match the orientation of a flanged to a selected target face, or create a flange with no offset from a selected edge.